Font Sizes

Posted on: December 01, 2009

Following is a handy matrix for those among us who like to indicate HTML
(font) sizes in "em"s. All modern browsers use a 16px default font size.
Specifying the font-size and line-height in ems (relative to the 16px
default font) allows the user to resize the font in the browser and
produces the most consistent results across different browsers.

For more about using em's, read:
http://www.alistapart.com/articles/howtosizetextincss